Method and system for predicting addition amount of slagging lime during lf refining, and lf refining method

ABSTRACT

A method and system for predicting an addition amount of slagging lime during ladle furnace (LF) refining, and an LF refining method are provided. The method includes: S1: calculating an actual sulfur distribution ratio in combination with a Kungliga Tekniska Högskolan (KTH) model and a least square method by using LF refining parameters; S2: calculating, according to a principle of sulfur mass conservation, a mass of final slag by using the LF refining parameters and the actual sulfur distribution ratio obtained in S1; and S3: calculating, according to a principle of material conservation during LF refining, an addition amount of slagging lime during the LF refining by using the LF refining parameters and the mass of the final slag obtained in S2, thereby predicting the addition amount of the required slagging lime.

CROSS REFERENCE TO THE RELATED APPLICATIONS

This application is based upon and claims priority to Chinese PatentApplication No. 202011257172.9, filed on Nov. 10, 2020, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the technical field of ferrousmetallurgy, and in particular, to a method and system for predicting anaddition amount of slagging lime during ladle furnace (LF) refining, andan LF refining method.

BACKGROUND

With the development of steel-making technologies, secondary refiningalso plays a vital role in the steel-making process. The LF is widelyapplied to steelmaking workshop because of its advantages such as thesmall equipment investment, flexible operation and desirable refiningeffect. Due to complex physicochemical reactions during refining,existing steel plants control an addition amount of the slaggingmaterial mainly by the continuous sampling and the operationalexperience of field operators, which causes the large componentfluctuation and unstable quality of molten steel, wastes materials, andseriously affects the improvement of production efficiency of the LF andthe advancement of full-process intelligent manufacturing technologiesof the steel plants. For example, the patent CN201410111982.1 provides amethod for determining an addition amount of a slagging material and adeoxidation alloy of an LF with a reference heat method. Hence, theresearch and development of modeling on the addition amount of theslagging material during LF refining becomes particularly significantunder the circumstance of advancing intelligent manufacturing in steelindustry.

Presently, researches on slagging during the LF refining mainly focus onanalysis of the slag system with respect to optimization and sulfurremoval mechanisms. During the LF refining, influences of convertertapping slag and casting residue need to be considered. Moreover, due tothe complex and uncontrollable reactions during the metallurgicalprocess, it is difficult to use a single metallurgical mechanism modelto realize the effective control on the addition amount of the slagginglime during the LF refining. Therefore, it is essential to research amethod for predicting the addition amount of the slagging lime duringthe LF refining with strong adaptation and accurate calculation to solvethe existing actual problems of the steel plants.

SUMMARY

In view of this, the present disclosure provides a method and system forpredicting an addition amount of slagging lime during LF refining, andan LF refining method, to solve the above problems of existing steelplants. The present disclosure provides a model to predict the additionamount of lime for desulfuration during LF refining with strongadaptation and accurate calculation in combination with mechanismanalysis and historical data analysis by fully mining actual datainformation of a production field. It can calculate an actual sulfurdistribution ratio and a mass of final slag according to components ofmolten steel, components of slag, a mass of the molten steel and a massof the slag during refining, and thus calculate the addition amount ofthe lime during LF refining quickly and accurately, thereby stabilizingthe components of the molten steel, saving materials, improving theproduction efficiency of the LF, and advancing full-process intelligentmanufacturing technologies of steel plants.

According to a first aspect of the present disclosure, a method forpredicting an addition amount of slagging lime during LF refining isprovided, which may specifically include the following steps:

S1: calculating an actual sulfur distribution ratio in combination witha Kungliga Tekniska Högskolan (KTH) model and a least square method byusing LF refining parameters;

S2: calculating a mass of final slag according to a principle of sulfurmass conservation by using the LF refining parameters and the actualsulfur distribution ratio obtained in S1; and

S3: calculating, according to a principle of material conservationduring LF refining, an addition amount of slagging lime during the LFrefining by using the LF refining parameters and the mass of the finalslag obtained in S2, thereby predicting the addition amount of therequired slagging lime.

Further, S1 may specifically include: calculating the actual sulfurdistribution ratio in combination with the KTH model and the leastsquare method by using a mass percent of each component in target slagand a mass percent of each component in target molten steel during theLF refining.

Further, the actual sulfur distribution ratio may be calculated with thefollowing steps:

defining a formula for a sulfur distribution ratio, as shown in Formula(1):

$\begin{matrix}{L_{S} = \frac{w(S)}{w\lbrack S\rbrack}} & (1)\end{matrix}$

where, w[S] denotes a mass percent of sulfur in the molten steel, inunit of %; w(S) denotes a mass percent of sulfur in the slag, in unit of%; and L_(S) denotes the sulfur distribution ratio;

denoting a sulphide capacity with Formula (2) in the KTH model:

$\begin{matrix}{C_{S} = {{\exp{\left\{ {- \frac{\Delta\; G^{\theta}}{RT}} \right\} \cdot \left\{ \frac{a_{0^{2 -}}}{f_{s^{2 -}}} \right\}}} = {\exp{\left\{ {- \frac{\Delta\; G^{\theta}}{RT}} \right\} \cdot \exp}\left\{ {- \frac{\zeta}{RT}} \right\}}}} & (2)\end{matrix}$

where, C_(s) denotes the sulphide capacity; ΔG⁰ denotes Gibbs freeenergy and is indicated as ΔG⁰=118535−58.8157·T(J/mol) R denotes gasconstant and is 8.314 (J/mol·K); and ζ denotes a function of a singlecomponent with respect to a temperature in case of no interactionbetween components;

defining a relation between a steel-slag sulfur equilibrium distributionratio L_(S)′ and C_(s), as shown in Formula (3):

$\begin{matrix}{{\lg\mspace{11mu} L_{S}^{\prime}} = {{\lg\mspace{11mu}\frac{w(S)}{w\lbrack S\rbrack}} = {{- \frac{935}{T}} + 1.375 + {\lg\mspace{11mu} f_{S}} + {\lg\; C_{S}} - {\lg\mspace{11mu} a_{\lbrack O\rbrack}}}}} & (3)\end{matrix}$

where, L_(S)′ denotes a sulfur distribution ratio calculated with theKTH model; T denotes a temperature, in unit of K; f_(s) denotes anactivity coefficient of sulfur in the molten steel; C_(s) denotes thesulphide capacity; and a_([O]) denotes an activity of oxygen in themolten steel; and

correcting, by using the least square method, the sulfur distributionratio calculated with the KTH model to obtain an actual sulfurdistribution ratio formula, as shown in Formula (4):

L _(S) =α+bR+cMI+dL _(S)′  (4)

where, L_(S) denotes the actual sulfur distribution ratio; R denotes abasicity of the furnace slag; MI denotes a Mannesmann index of thefurnace slag; a denotes a constant term; b denotes a weight coefficientof the basicity; c denotes a weight coefficient of the Mannesmann index;and d denotes a weight coefficient of the sulfur distribution ratiocalculated by the KTH model.

Further, S2 may specifically include: calculating, according to theprinciple of sulfur mass conservation that a decreased amount of thesulfur in the molten steel equals to an increased amount of the sulfurin the slag, the mass of the final slag in combination of a mass percentof each component in initial molten steel, a mass percent of eachcomponent in the target molten steel, a mass percent of each componentin the final slag, a mass percent and a mass of each component incasting residue, a mass percent and a mass of each component inconverter tapping slag, a mass of the molten steel and the actual sulfurdistribution ratio obtained in S1.

Further, a final slag mass calculation model may include:

(w[S]₀−_(w)[S])·G_(m) =w(S)·M_(z) −w(S)_(h)·M_(h) −w(S)_(c)·M_(c)  (5)

where, w[S]₀ is a mass percent of sulfur in the initial molten steel, inunit of %; w[S] is a mass percent of sulfur in the molten steel at asmelting endpoint, in unit of %; w(S) is a mass percent of sulfur in thefinal slag, in unit of %; w(S)_(h) is a mass percent of sulfur in thecasting residue, in unit of %; w(S), is a mass percent of sulfur in theconverter tapping slag, in unit of %; G_(m) is the mass of the moltensteel, in unit of kg; M_(z) is the mass of the final slag, in unit ofkg; M_(h) is a mass of the casting residue, in unit of kg; and M_(c) isa mass of the converter tapping slag, in unit of kg; and

substituting Formula (1) into Formula (5) to obtain a final slag masscalculation formula, as shown in Formula (6):

$\begin{matrix}{M_{z} = \frac{{\left( {{w\lbrack S\rbrack}_{o} - {w\lbrack S\rbrack}} \right) \cdot G_{m}} + {{w(S)}_{h} \cdot M_{h}} + {{w(S)}_{c} \cdot M_{c}}}{{w\lbrack S\rbrack} \cdot L_{S}}} & (6)\end{matrix}$

Further, S3 may specifically include: respectively obtaining, accordingto the principle of material conservation during the LF refining byusing the LF refining parameters and the mass of the final slag obtainedin S2, a mass M₁ of lime required to remove the sulfur from the moltensteel, a calculated mass M₂ of lime required to adjust a basicity ofrefining slag and a calculated mass M₃ of lime required to reach themass of the final slag, and adding the M₁, the M₂ and the M₃, to obtainthe addition amount M of the slagging lime during the LF refining,thereby predicting the addition amount of the required slagging lime.

Further, owing to elemental mass conservation before and after sulfurremoval, the mass M₁ of the lime required to remove the sulfur from themolten steel may be obtained from the following Formula (7):

M₁·(% CaO)/56=G_(m)(w[S]₀ −w[S])/32  (7)

according to a basic basicity calculation formula, the calculated massM₂ of the lime required to adjust the basicity of the refining slag maybe obtained from the following Formula (8):

$\begin{matrix}{R_{1} = \frac{\begin{matrix}{{M_{c}\left( {\%\mspace{11mu}{CaO}} \right)}_{c} + {\left( {M_{1} + M_{2} + M_{y}} \right) \cdot \left( {\%\mspace{11mu}{CaO}} \right)} +} \\{{M_{l}\left( {\%\mspace{11mu}{CaO}} \right)}_{l} + {M_{h}\left( {\%\mspace{11mu}{CaO}} \right)}_{h}}\end{matrix}}{{M_{c}\left( {\%\mspace{11mu}{SiO}_{2}} \right)}_{c} + {M_{l}\left( {\%\mspace{11mu}{SiO}_{2}} \right)}_{l} + {M_{h}\left( {\%\mspace{11mu}{SiO}_{2}} \right)}_{h} + M_{Si}}} & (8)\end{matrix}$

according to the principle of material conservation, the calculated massM₃ of the lime required to reach the mass of the final slag may beobtained from the following Formula (9):

M_(z)(% CaO)_(z)=M_(z)(% CaO)+[(M₁+M₂+M_(y))·(% CaO)]+M_(c)(%CaO)_(c)+M_(c)(% CaO)_(c)+M_(h)(% CaO)_(h)+M_(l)(% CaO)_(l)   (9) and

adding the M₁, the M₂ and the M₃ to obtain the addition amount M of theslagging lime during the LF refining from the following Formula (10),thereby completing prediction:

M=M₁+M₂+M₃  (10)

where, (% CaO) is a mass percent of CaO in the lime, in unit of %; M₁ isthe mass of the lime required to remove the sulfur from the moltensteel, in unit of kg; G_(m) is the mass of the molten steel, in unit ofkg; M₂ is the calculated mass of the lime required to adjust thebasicity of the refining slag, in unit of kg; M₁ is a mass ofpre-melting refining slag added during tapping, in unit of kg; M_(y) isa mass of lime added during the tapping, in unit of kg; M_(h) is themass of the casting residue, in unit of kg; M_(c) is the mass of theconverter tapping slag, in unit of kg; M₃ is the calculated mass of thelime required to reach the mass of the final slag, in unit of kg; M_(Si)is a mass of silicon dioxide generated during ferrosilicon deoxidation,in unit of kg; (% CaO)_(c) is a mass percent of CaO in the convertertapping slag, in unit of %; (% CaO)₁ is a mass percent of CaO in thepre-melting refining slag added during the tapping, in unit of %; (%CaO)_(h) is a mass percent of CaO in the casting residue, in unit of %;(% CaO)_(z) is a mass percent of CaO in the final slag, in unit of %; (%SiO₂)c is a mass percent of Sift in the converter tapping slag, in unitof %; (% SiO₂)₁ is a mass percent of SiO₂ in the pre-melting refiningslag added during the tapping, in unit of %; (% SiO₂)_(h) is a masspercent of SiO₂ in the casting residue, in unit of %; and R₁ is abasicity of target refining slag and is calculated by thermodynamicsimulation.

According to a second aspect of the present disclosure, a system forpredicting an addition amount of slagging lime during LF refining isprovided, which may include:

an actual sulfur distribution ratio calculation module, configured tocalculate an actual sulfur distribution ratio in combination with a KTHmodel and a least square method by using LF refining parameters;

a final slag mass calculation module, configured to calculate a mass offinal slag according to a principle of sulfur mass conservation by usingthe LF refining parameters and the actual sulfur distribution ratioobtained in S1; and

a lime addition amount prediction module, configured to calculate,according to a principle of material conservation during LF refining, anaddition amount of slagging lime during the LF refining by using the LFrefining parameters and the mass of the final slag obtained in S2,thereby predicting the addition amount of the required slagging lime.

According to a third aspect of the present disclosure, an LF refiningmethod is provided, which may include the following steps:

S1: acquiring initial parameters of LF refining;

S2: pre-processing the initial parameters, and correcting error datatherein;

S3: predicting an addition amount of required slagging lime by using theprediction method in the first aspect of the present disclosure;

S4: starting the LF refining according to a prediction result, andcontinuously acquiring refining parameters during refining; and

S5: determining whether a mass percent of sulfur in molten steel at arefining endpoint is qualified;

if the mass percent of the sulfur is qualified, performing awire-feeding operation till completion of the LF refining; and

if the mass percent of the sulfur is unqualified, iterating refiningparameters at the refining endpoint to the parameters in S1 to take asnew initial parameters, and repeating the above steps.

Further, the parameters may include: inbound parameters, outboundparameters and production parameters;

the inbound parameters may include a mass percent of each component ininbound molten steel, a mass of molten steel, a mass percent of eachcomponent in converter tapping slag, a mass of the converter tappingslag, a mass percent of each component in casting residue, and a mass ofthe casting residue;

the outbound parameters may include a mass percent of each component intarget molten steel, and a mass percent of each component in targetslag; and

the production parameters may include a mass percent of each componentin lime, and a mass of the lime.

Compared with the prior art, the method and system for predicting anaddition amount of slagging lime during LF refining, and the LF refiningmethod provided by the present disclosure have the following advantages:

The present disclosure calculates an actual sulfur distribution ratio, amass of final slag, and an addition amount of lime required for slaggingduring the LF refining, and provides a novel model construction methodfor an LF refining system that lacks a slagging model. The presentdisclosure constructs a model to predict the addition amount of lime fordesulfuration during LF refining in combination with metallurgicalmechanism analysis and big data processing. The slagging sulfur-removallime addition amount predicted by the model has a required deviation ofwithin 20% for lime added at a time and a mass percent of successfullyhit endpoint S, and can be well applied to prediction of the additionamount of the lime in which the mass percent of the target sulfur is0.004%-0.005%. While saving the production cost and improving theaccuracy of process operation, the construction of the model reduces thelabor intensity and further improves the LF refining efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings described herein are provided for furtherunderstanding of the present disclosure, and constitute a part of thepresent disclosure. The exemplary examples and illustrations of thepresent disclosure are intended to explain the present disclosure, butdo not constitute inappropriate limitations to the present disclosure.

In the drawings:

FIG. 1 is a flow chart of a method for predicting an addition amount ofslagging lime during LF refining according to the present disclosure.

FIG. 2 is a flow chart of an LF refining method according to the presentdisclosure.

DETAILED DESCRIPTION

Descriptions will now be made in detail to exemplary examples, instancesof which are illustrated in the accompanying drawings. The followingdescription refers to the accompanying drawings in which the samenumbers in different drawings represent the same or similar elementsunless otherwise represented. The implementations set forth in thefollowing description of exemplary examples do not represent allimplementations consistent with the present disclosure. Instead, theyare merely examples of apparatuses and methods consistent with aspectsrelated to the present disclosure as recited in the appended claims.

It should be noted that the terms “first”, “second”, and so on in thedescription and claims of the present disclosure are intended todistinguish between similar objects but do not necessarily indicate aspecific order or sequence. It should be understood that data used insuch a way may be interchangeable in a certain case, such that theexamples of the present invention described here can be implemented inan order other than those illustrated or described here. Moreover, theterms “include”, “have”, and any other variants mean to cover thenon-exclusive inclusion, for example, a process, method, system,product, or device that includes a list of steps or units isunnecessarily limited to those steps or units, but may include othersteps or units not expressly listed or inherent to such a process,method, system, product, or device.

The term “multiple” means to involve two or more things.

It should be understood that the term “and/or” used in the presentdisclosure merely describes an association relationship betweenassociated objects, indicating that there may be three kinds ofrelationships. For example, A and/or B may indicate three cases: the Aexists alone, both the A and the B coexist, and the B exists alone.

As shown in FIG. 1, the present disclosure provides the method forpredicting the addition amount of slagging lime during LF refining. Themethod may include the following steps:

S1: Obtain the actual sulfur distribution ratio calculation model withthe KTH model as a basis in combination with the mass percent of eachcomponent in the target slag system and the mass percent of eachcomponent in target molten steel during LF refining, where, the KTHmodel developed by the department of metallurgy from the KungligaTekniska Högskolan is configured to calculate the sulphide capacity ofthe multi-component slag system at different temperatures.

S2: Obtain the final slag mass calculation model according to theprinciple of S mass conservation in combination of the mass percent ofeach component in initial molten steel, the mass percent of eachcomponent in the target molten steel, the mass percent of each componentin final slag, the mass percent and the mass of each component incasting residue, the mass percent and the mass of each component inconverter tapping slag, the mass of molten steel and the actual sulfurdistribution ratio.

S3: Obtain the refining sulfur-removal lime addition amount calculationmodel according to the principle of material conservation duringrefining, thereby predicting an addition amount of lime required duringthe LF refining.

As shown in FIG. 2, in actual applications, the lime addition amountmodel of the method is applied with the following steps:

S1: Acquire initial parameters of LF refining.

Acquire inbound parameters during the LF refining, the inboundparameters including the mass percent of each component in inboundmolten steel, the mass of molten steel, the mass percent of eachcomponent in converter tapping slag, the mass of the converter tappingslag, the mass percent of each component in casting residue, and themass of the casting residue.

Acquire outbound parameters during the LF refining, the outboundparameters including the mass percent of each component in target moltensteel, and the mass percent of each component in the target slag system.

Acquire production parameters during the LF refining, the productionparameters including the mass percent of each component in lime and themass of the lime.

(2) Pre-process historical data, and remove abnormal data caused by thesystem reason or the artificial reason in the production report.

(3) Establish the model to predict the addition amount of lime forslagging sulfur-removal according to the inbound parameters, theoutbound parameters and the production parameters of the LF refining inthe pre-processed initial parameters.

(4) Restart smelting according to the established the model to predictthe addition amount of lime for slagging sulfur-removal, and acquirerefining parameters in real time.

(5) Test components of molten steel when the smelting is close to anendpoint, and determine whether the mass percent of endpoint sulfur ofthe molten steel is qualified. If yes, execute the next step of thewire-feeding operation till completion of the LF refining; and if no,iterate refining parameters at this time to S1 to calibrate the themodel to predict the addition amount of lime for slaggingsulfur-removal.

For the actual sulfur distribution ratio calculation model in S1, theactual sulfur distribution ratio calculation model is established incombination with the mass percent of each component in the target slagsystem and the mass percent of each component in the target molten steelduring the LF refining by using the big data mining method on the basisof analysis on field actual data, as shown in Formulas (1)-(3):

Define the formula for the sulfur distribution ratio, as shown inFormula (1):

$\begin{matrix}{L_{S} = \frac{w(S)}{w\lbrack S\rbrack}} & (1)\end{matrix}$

where, w[S] denotes the mass percent of sulfur in the molten steel, inunit of %; w(S) denotes the mass percent of sulfur in the slag, in unitof %; and L_(S) denotes the sulfur distribution ratio.

Denote the sulphide capacity with Formula (2) in the KTH model:

$\begin{matrix}{C_{S} = {{\exp{\left\{ {- \frac{\Delta\; G^{\theta}}{RT}} \right\} \cdot \left\{ \frac{a_{o^{2}}}{f_{s^{2 -}}} \right\}}} = {\exp{\left\{ {- \frac{\Delta\; G^{\theta}}{RT}} \right\} \cdot \exp}\left\{ {- \frac{\zeta}{RT}} \right\}}}} & (2)\end{matrix}$

where, C_(s) denotes the sulphide capacity; ΔG⁰ denotes Gibbs freeenergy and is indicated as ΔG⁰=118535−58.8157·T(J/mol); R denotes gasconstant and is 8.314 (J/mol·K); and ζ denotes the function of thesingle component with respect to the temperature in case of nointeraction between components.

Define the relation between the steel-slag sulfur equilibriumdistribution ratio L_(S)′ and Cs, as shown in Formula (3):

$\begin{matrix}{{lgL}_{S}^{\prime} = {{\lg\frac{w(S)}{w\lbrack S\rbrack}} = {{- \frac{935}{T}} + 1.375 + {lgf}_{S} + {lgC}_{S} - {\lg\mspace{11mu} a_{\lfloor O\rfloor}}}}} & (3)\end{matrix}$

where, L_(S)′ denotes the sulfur distribution ratio calculated with theKTH model; T denotes the temperature, in unit of K; f_(s) denotes theactivity coefficient of the sulfur in the molten steel; C_(s) denotesthe sulphide capacity; and a_(└O┘) denotes the activity of oxygen in themolten steel.

Optimize the model based on the KTH model according to the field actualdata to obtain the following Formula (4)

L _(S)=224.543+54.947·R+3359.397MI−4.544L _(S)′  (4)

where, L_(S) denotes the actual sulfur distribution ratio; R denotes thebasicity of the furnace slag, with the application range of 3.33-4.58;and MI denotes the Mannesmann index of the furnace slag, with anapplication range of 0.13-0.31.

In S2, establish the final slag mass calculation model according to theprinciple of S mass conservation in combination of the mass percent ofeach component in the initial molten steel, the mass percent of eachcomponent in the target molten steel, the mass percent of each componentin the final slag, the mass percent and the mass of each component inthe casting residue, the mass percent and the mass of each component inthe converter tapping slag, the mass of the molten steel and the actualsulfur distribution ratio, as shown in Formula (5) and Formula (6):

(w[S]₀ −w[S])·G_(m) =w(S)·M_(z) −w(S)_(h)·M_(h) −w(S)_(c)·M_(c)  (5)

where, w[S]₀ is the mass percent of sulfur in the initial molten steel,in unit of %; w[S] is the mass percent of sulfur in the molten steel, inunit of %; w(S) is the mass percent of sulfur in the final slag, in unitof %; w(S)_(h) is the mass percent of sulfur in the casting residue, inunit of %; w(S)_(c) is the mass percent of sulfur in the convertertapping slag, in unit of %; G_(m) is the mass of the molten steel, inunit of kg; M_(z) is the mass of the final slag, in unit of kg; M_(h) isthe mass of the casting residue, in unit of kg; and M_(c) is the mass ofthe converter tapping slag, in unit of kg.

Substituting Formula (1) into Formula (5) to obtain the final slag masscalculation formula, as shown in Formula (6):

$\begin{matrix}{M_{z} = \frac{{\left( {{w\lbrack S\rbrack}_{0} - {w\lbrack S\rbrack}} \right) \cdot G_{m}} + {{w(S)}_{h} \cdot M_{h}} + {{w(S)}_{c} \cdot M_{c}}}{{w\lbrack S\rbrack} \cdot L_{S}}} & (6)\end{matrix}$

In S3, establish the refining sulfur-removal lime addition amountcalculation model according to the principle of material conservationduring the refining in combination with the mass percent of eachcomponent in the initial molten steel, the mass percent of eachcomponent in the target molten steel, the mass of the molten steel, themass percent of CaO in lime, the mass percent of each component in thecasting residue, the mass of the casting residue, the mass percent ofeach component in the converter tapping slag, and the mass of theconverter tapping slag, as shown in the following formula:

$\left\{ {R_{1} = \frac{\frac{\begin{matrix}{{M_{1} \cdot \left( {\%\mspace{14mu}{CaO}} \right)} = {{G_{m}\left( {{w\lbrack S\rbrack}_{0} - {w\lbrack S\rbrack}} \right)}{56/32}}} \\\begin{matrix}{{M_{c}\left( {\%\mspace{14mu}{CaO}} \right)}_{c} + {\left( {M_{1} + M_{2} + M_{y}} \right) \cdot \left( {\%\mspace{11mu}{CaO}} \right)} +} \\{{M_{l}\left( {\%\mspace{11mu}{CaO}} \right)}_{l} + {M_{h}\left( \;{\%\mspace{11mu}{CaO}} \right)}_{h}}\end{matrix}\end{matrix}}{\begin{pmatrix}{M_{c} + M_{1} + M_{2} + M_{3} +} \\{M_{4} + M_{h} + M_{Si} + M_{{CaF}_{2}}}\end{pmatrix}}}{\frac{\begin{matrix}{{M_{c}\left( {\%\mspace{11mu}{SiO}_{2}} \right)}_{c} + {M_{l}\left( {\%\mspace{14mu}{SiO}_{2}} \right)}_{l} +} \\{{M_{h}\left( {\%\mspace{11mu}{SiO}_{2}} \right)}_{b} + M_{Si}}\end{matrix}}{\begin{matrix}\begin{matrix}\begin{matrix}\begin{matrix}\begin{pmatrix}{M_{c} + M_{1} + M_{2} + M_{3} +} \\{M_{4} + M_{h} + M_{Si} + M_{{CaF}_{2}}}\end{pmatrix} \\{{M_{3}\left( {\%\mspace{11mu}{CaO}} \right)} = {{M_{z}\left( {\%\mspace{14mu}{CaO}} \right)}_{z} -}}\end{matrix} \\{\left\lbrack {\left( {M_{1} + M_{2} + M_{y}} \right) \cdot \left( {\%\mspace{14mu}{CaO}} \right)} \right\rbrack -}\end{matrix} \\{{M_{c}\left( {\%\mspace{14mu}{CaO}} \right)}_{c} - {M_{h}\left( {\%\mspace{14mu}{CaO}} \right)}_{h} - {M_{i}\left( {\%\mspace{11mu}{CaO}} \right)}_{l}}\end{matrix} \\{M = {M_{1} + M_{2} + M_{3}}}\end{matrix}}}} \right.$

where, (% CaO) is the mass percent of the CaO in the lime, in unit of %;M₁ is the mass of lime required to remove the sulfur from the moltensteel, in unit of t; G_(m) is the mass of the molten steel, in unit ofkg; M₂ is the calculated mass of lime required to adjust the basicity ofthe refining slag, in unit of kg; M₁ is the mass of pre-melting refiningslag added during tapping, in unit of kg; M_(y) is the mass of limeadded during the tapping, in unit of kg; M_(h) is the mass of thecasting residue, in unit of kg; Mc is the mass of the converter tappingslag, in unit of kg; M₃ is the calculated mass of lime required to reachthe mass of the final slag, in unit of kg; M₄ is the mass of steel shotaluminum added during the tapping, in unit of kg; M_(Si) is the mass ofsilicon dioxide generated during ferrosilicon deoxidation, in unit ofkg; M_(CaF2) is the mass of fluorite, in unit of kg: (% CaO)_(c) is themass percent of CaO in the converter tapping slag, in unit of %; (%CaO)_(l) is the mass percent of CaO in the pre-melting refining slagadded during the tapping, in unit of %; (% CaO)_(h) is the mass percentof CaO in the casting residue, in unit of %; (% CaO)_(z) is the masspercent of CaO in the final slag, in unit of %; (% SiO₂)c is the masspercent of SiO₂ in the converter tapping slag, in unit of %; (%SiO₂)_(l) is the mass percent of SiO₂ in the pre-melting refining slagadded during the tapping, in unit of %; (% SiO₂)_(h) is the mass percentof SiO₂ in the casting residue, in unit of %; and R₁ is the basicity oftarget refining slag and is calculated by thermodynamic simulation. Themass of the required lime that is calculated through the above model isused to guide the addition of the lime in actual production based on theanticipated mass percent of the endpoint sulfur of the molten steel.

Example

With SS400 steel produced by the 150 t LF of some steel plant as theimplementation carrier, when the LF refining starts, the addition amountof lime is calculated with the refining sulfur-removal lime additionamount calculation model according to inbound parameters, productionparameters and outbound parameters during the LF refining. Table 1 showsthe mass percent of each component in the target slag system of theSS400 steel, with the relevant experimental data as shown in Table 2. Ascan be seen from experimental results, the slagging sulfur-removal limeaddition amount predicted by the model has the required deviation ofwithin 20% for lime added at a time and the mass percent of successfullyhit endpoint S, and can be well applied to prediction of the additionamount of the lime in which the mass percent of the target sulfur is0.004%-0.005%.

TABLE 1 Mass percent of each component in the target slag system of theSS400 steel, % Slag component CaO SiO₂ MgO Al₂O₃ Mass percent of eachcomponent 50-55 12-15 5-8 15-25

TABLE 2 Experimental results after implementation of the presentdisclosure Mass percent of Balance Addition initial sulfur Molten inW[s]actual w[s] amount in molten steel rotary Actual measured Target oflime steel amount/ casting/ calculated M1/ M2/ M3/ value/ value/ M/Example w[s]₀/% kg kg Ls kg kg kg % % kg  1 0.018 158000 3000 277.3 4416 507 0.0040 0.0040 566  2 0.017 161000 3000 272.5 41 11 471 0.00320.0040 524  3 0.018 156000 3000 275.5 43 16 515 0.0038 0.0040 574  40.02 153000 2000 257.9 48 33 658 0.0035 0.0040 739  5 0.019 160000 2000254.5 47 27 671 0.0034 0.0040 745  6 0.02 153000 3500 290.2 48 25 5430.0045 0.0050 616  7 0.025 153000 3000 306.4 63 12 645 0.0043 0.0050 721 8 0.021 153000 3000 287.2 51 18 581 0.0048 0.0050 650  9 0.032 1580001500 321.0 87 23 900 0.0042 0.0050 1010 10 0.021 155000 2000 264.8 52 36680 0.0046 0.0050 768

It is to be noted that the terms “include”, “contain” or any othervariations thereof are intended to cover a non-exclusive inclusion, suchthat a process, method, article or equipment including a series ofelements not only includes those elements, but also includes thoseelements that are not explicitly listed, or includes elements inherentto such a process, method, article or device. Under the condition of nomore limitations, it is not excluded that additional identical elementsfurther exist in the process, method, article or device includingelements defined by a sentence “including a . . . ”.

The serial numbers of the examples of the present disclosure are merelyfor description and do not represent the preference of the examples.

The examples of the present disclosure have been described above withreference to the accompanying drawings, but the present disclosure isnot limited to the foregoing specific examples. The foregoing specificexamples are only illustrative and not restrictive. Under theinspiration of the present disclosure, those of ordinary skill in theart can make many improvements without departing from the purpose of thepresent disclosure and the protection scope defined by the claims, andthese improvements shall fall within the protection scope of the presentdisclosure.

1. (canceled)
 2. A system for predicting an addition amount of aslagging lime during a ladle furnace (LF) refining, wherein the systemcomprises: an actual sulfur distribution ratio calculation module,configured to calculate an actual sulfur distribution ratio incombination with a Kungliga Tekniska Högskolan (KTH) model and a leastsquare method by using LF refining parameters, wherein the LF refiningparameters comprise a mass percent of each component in a target slagand a mass percent of each component in a target molten steel during LFrefining; a final slag mass calculation module, configured to calculatea mass of a final slag according to a principle of sulfur massconservation by using the LF refining parameters and the actual sulfurdistribution ratio; and a lime addition amount prediction module,configured to calculate, according to a principle of materialconservation during the LF refining, the addition amount of the slagginglime during the LF refining by using the LF refining parameters and amass of a final slag, thereby predicting the addition amount of theslagging lime, wherein the mass of the final slag is obtained by usingthe LF refining parameters and the actual sulfur distribution ratio;wherein the system uses a method for predicting the addition amount ofthe slagging lime during the ladle furnace (LF) refining, comprising:calculating the actual sulfur distribution ratio in combination with theKungliga Tekniska Högskolan (KTH) model and the least square method byusing the LF refining parameters; calculating the mass of the final slagby using the LF refining parameters and the actual sulfur distributionratio; and calculating the addition amount of the slagging lime duringthe LF refining by using the LF refining parameters and the mass of thefinal slag, thereby predicting the addition amount of the slagging lime;the actual sulfur distribution ratio is calculated with the followingsteps: defining a formula for a sulfur distribution ratio, as shown inFormula (1): $\begin{matrix}{{L_{S} = \frac{w(S)}{w\lbrack S\rbrack}},} & (1)\end{matrix}$ wherein, w[S] denotes a mass percent of sulfur in a moltensteel, in unit of %; w(S) denotes a mass percent of sulfur in a slag, inunit of %; and L_(S) denotes the sulfur distribution ratio; denoting asulphide capacity with Formula (2) in the KTH model: $\begin{matrix}{{C_{S} = {{\exp{\left\{ {- \frac{\Delta\; G^{\theta}}{RT}} \right\} \cdot \left\{ \frac{a_{o^{2}}}{f_{s^{2 -}}} \right\}}} = {\exp{\left\{ {- \frac{\Delta\; G^{\theta}}{RT}} \right\} \cdot \exp}\left\{ {- \frac{\zeta}{RT}} \right\}}}},} & (2)\end{matrix}$ wherein, C_(s) denotes the sulphide capacity; ΔG^(θ)denotes Gibbs free energy and is indicated as ΔG^(θ)=118535−58.8157·T,in unit of J/mol; R denotes gas constant and is 8.314 (J/mol·K): ζdenotes a function of a single component with respect to a temperaturein case of no interaction between components; f_(s) ²⁻ denotes anactivity coefficient of sulfur in the slag; and α_(o) ²⁻ denotes anactivity of oxygen in the slag; defining a relation between a steel-slagsulfur equilibrium distribution ratio L_(S)′ and Cs, as shown in Formula(3): $\begin{matrix}{{{\lg\mspace{11mu} L_{S}^{\prime}} = {{\lg\frac{w(S)}{w\lbrack S\rbrack}} = {{- \frac{935}{T}} + 1.375 + {\lg\mspace{11mu} f_{S}} + {\lg\mspace{11mu} C_{S}} - {\lg\mspace{11mu} a_{\lfloor O\rfloor}}}}},} & (3)\end{matrix}$ wherein, L_(S)′ denotes a sulfur distribution ratiocalculated with the KTH model; T denotes the temperature, in unit of K;f_(s) denotes an activity coefficient of sulfur in the molten steel;C_(s) denotes the sulphide capacity; and a_([O]) denotes an activity ofoxygen in the molten steel; and correcting by using the least squaremethod, the sulfur distribution ratio calculated with the KTH model toobtain an actual sulfur distribution ratio calculation formula, as shownin Formula (4):L _(S) =α+bR+cMI+dL _(S)′  (4) wherein, L_(S) denotes the sulfurdistribution ratio; R denotes a basicity of a furnace slag; MI denotes aMannesmann index of the furnace slag; a denotes a constant term; bdenotes a weight coefficient of the basicity; c denotes a weightcoefficient of the Mannesmann index; and d denotes a weight coefficientof the sulfur distribution ratio calculated by the MTH model; whereincalculating the mass of the final slag by using the LF refiningparameters and the actual sulfur distribution ratio comprises:calculating, according to a principle of sulfur mass conservation that adecreased amount of the sulfur in the molten steel equals to anincreased amount of the sulfur in the slag, the mass of the final slagin combination of a mass percent of each component in an initial moltensteel, the mass percent of each component in the target molten steel, amass percent of each component in the final slag, a mass percent and amass of each component in a casting residue, a mass percent and a massof each component in a converter tapping slag, a mass of the moltensteel and the actual sulfur distribution ratio; a final slag masscalculation model comprises:(w[S]₀ −w[S])·G_(m) =w(S)·M_(z) −w(S)_(h)·M_(h) −w(S)_(c)·M_(c)  (5),wherein, w[S]₀ is a mass percent of sulfur in the initial molten steel,in unit of %; w[S] is the mass percent of sulfur in the molten steel ata smelting endpoint, in unit of %; w(S) is the mass percent of sulfur inthe final slag, in unit of %; w(S)_(h) is a mass percent of sulfur inthe casting residue, in unit of %; w(S)_(c) is a mass percent of sulfurin the converter tapping slag, in unit of %; G_(m) is the mass of themolten steel, in unit of kg; M_(z) is the mass of the final slag, inunit of kg; M_(h) is a mass of the casting residue, in unit of kg; andM_(c) is a mass of the converter tapping slag, in unit of kg; andsubstituting the Formula (1) into the Formula (5) to obtain a final slagmass calculation formula, as shown in Formula (6): $\begin{matrix}{{M_{z} = \frac{{\left( {{w\lbrack S\rbrack}_{0} - {w\lbrack S\rbrack}} \right) \cdot G_{m}} + {{w(S)}_{h} \cdot M_{h}} + {{w(S)}_{c} \cdot M_{c}}}{{w\lbrack S\rbrack} \cdot L_{S}}};} & (6)\end{matrix}$ respectively obtaining, according to a principle ofmaterial conservation during the LF refining by using the LF refiningparameters and the mass of the final slag, a mass M₁ of lime required toremove the sulfur from the molten steel, a calculated mass M₂ of limerequired to adjust a basicity of refining slag and a calculated mass M₃of lime required to reach the mass of the final slag, and adding the M₁,the M₂ and the M₃, to obtain the addition amount M of the slagging limeduring the LF refining, thereby predicting the addition amount of theslagging lime; according to elemental mass conservation before and aftersulfur removal, the mass M₁ of the lime required to remove the sulfurfrom the molten steel is obtained from the following Formula (7):M₁·(% CaO)/56=G_(m)(w[S]₀ −w[S])/32  (7), according to a basic basicitycalculation formula, the calculated mass M₂ of the lime required toadjust the basicity of the refining slag is obtained from the followingFormula (8): $\begin{matrix}{{R_{1} = \frac{\begin{matrix}{{M_{c}\left( {\%\mspace{11mu}{CaO}} \right)}_{c} + {\left( {M_{1} + M_{2} + M_{y}} \right) \cdot \left( {\%\mspace{11mu}{CaO}} \right)} +} \\{{M_{l}\left( {\%\mspace{11mu}{CaO}} \right)}_{l} + {M_{h}\left( \;{\%\mspace{11mu}{CaO}} \right)}_{h}}\end{matrix}}{\begin{matrix}{{M_{c}\left( {\%\mspace{11mu}{SiO}_{2}} \right)}_{c} + {M_{l}\left( {\%\mspace{14mu}{SiO}_{2}} \right)}_{l} +} \\{{M_{h}\left( {\%\mspace{11mu}{SiO}_{2}} \right)}_{b} + M_{Si}}\end{matrix}}},} & (8)\end{matrix}$ according to the principle of material conservation, thecalculated mass M₃ of the lime required to reach the mass of the finalslag is obtained from the following Formula (9):M_(z)(% CaO)_(z)=M_(z)(% CaO)+[(M₁+M₂+M_(y))·(% CaO)]+M_(c)(%CaO)_(c)+M_(h)(% CaO)_(h)+M_(l)(% CaO);   (9); adding the M₁, the M₂ andthe M₃ to obtain the addition amount M of the slagging lime during theLF refining from the following Formula (10), thereby completingprediction:M=M₁+M₂+M₃  (10) wherein, w[S]₀ is the mass percent of sulfur in theinitial molten steel, in unit of %, w[S] is the mass percent of sulfurin the molten steel at a smelting endpoint, in unit of %; M_(z) is themass of the final slag, in unit of kg; M_(h) is the mass of the castingresidue, in unit of kg; and M_(c) is the mass of the converter tappingslag, in unit of kg; (% CaO) is a mass percent of CaO in the lime, inunit of %; M₁ is the mass of the lime required to remove the sulfur fromthe molten steel, in unit of kg; G_(m) is the mass of the molten steel,in unit of kg; M₂ is the calculated mass of the lime required to adjustthe basicity of the refining slag, in unit of kg; M_(l) is a mass ofpre-melting refining slag added during tapping, in unit of kg; M_(y) isa mass of lime added during the tapping, in unit of kg; M₃ is thecalculated mass of the lime required to reach the mass of the finalslag, in unit of kg; M_(Si) is a mass of silicon dioxide generatedduring ferrosilicon deoxidation, in unit of kg; (% CaO)_(c) is a masspercent of CaO in the converter tapping slag, in unit of %; (% CaO)_(l)is a mass percent of CaO in the pre-melting refining slag added duringthe tapping, in unit of %; (% CaO)_(h) is a mass percent of CaO in thecasting residue, in unit of %; (% CaO)_(z) is a mass percent of CaO inthe final slag, in unit of %; (% SiO₂)_(c) is a mass percent of SiO₂ inthe converter tapping slag, in unit of %; (% SiO₂)_(l) is a mass percentof SiO₂ in the pre-melting refining slag added during the tapping, inunit of %; (% SiO₂)_(h) is a mass percent of SiO₂ in the castingresidue, in unit of %; and R₁ is a basicity of a target refining slagand is calculated by a thermodynamic simulation.
 3. A ladle furnace (LF)refining method, comprising the following steps: S1: acquiring initialparameters of LF refining; S2: pre-processing the initial parameters,and correcting error data therein; S3: predicting the addition amount ofthe slagging lime by using a prediction method for predicting anaddition amount of a slagging lime during ladle furnace (LF) refining;S4: starting the LF refining according to a prediction result, andcontinuously acquiring refining parameters during the LF refining; andS5: determining whether a mass percent of sulfur in a molten steel at arefining endpoint is qualified; if the mass percent of the sulfur isqualified, performing a wire-feeding operation till completion of the LFrefining; and if the mass percent of the sulfur is unqualified,iterating refining parameters at the refining endpoint to the parametersin S1 to take as new initial parameters, and repeating the above steps;wherein the prediction method comprises: calculating an actual sulfurdistribution ratio in combination with a Kungliga Tekniska Högskolan(KTH) model and a least square method by using LF refining parameters,wherein the LF refining parameters comprise a mass percent of eachcomponent in a target slag and a mass percent of each component in atarget molten steel during LF refining; calculating a mass of a finalslag by using the LF refining parameters and the actual sulfurdistribution ratio; and calculating the addition amount of the slagginglime during the LF refining by using the LF refining parameters and themass of the final slag, thereby predicting the addition amount of theslanging lime; the actual sulfur distribution ratio is calculated withthe following steps: defining a formula for a sulfur distribution ratio,as shown in Formula (1): $\begin{matrix}{{L_{S} = \frac{w(S)}{w\lbrack S\rbrack}},} & (1)\end{matrix}$ wherein, w[S] denotes a mass percent of sulfur in a moltensteel, in unit of %; w(S) denotes a mass percent of sulfur in a slag, inunit of %; and L_(S) denotes the sulfur distribution ratio; denoting asulphide capacity with Formula (2) in the KTH model: $\begin{matrix}{{C_{S} = {{\exp{\left\{ {- \frac{\Delta\; G^{\theta}}{RT}} \right\} \cdot \left\{ \frac{a_{o^{2}}}{f_{s^{2 -}}} \right\}}} = {\exp{\left\{ {- \frac{\Delta\; G^{\theta}}{RT}} \right\} \cdot \exp}\left\{ {- \frac{\zeta}{RT}} \right\}}}},} & (2)\end{matrix}$ wherein, C_(s) denotes the sulphide capacity: ΔG^(θ)denotes Gibbs free energy and is indicated as ΔG^(θ)=1118535−58.8157·T,in unit of J/mol; R denotes gas constant and is 8.314 (J/mol·K); ζdenotes a function of a single component with respect to a temperaturein case of no interaction between components; f_(s) _(z−) denotes anactivity coefficient of sulfur in the slag; and α_(o) _(z−) denotes anactivity of oxygen in the slag; defining a relation between a steel-slagsulfur equilibrium distribution ratio L_(S)′ and Cs, as shown in Formula(3): $\begin{matrix}{{{\lg\mspace{11mu} L_{S}^{\prime}} = {{\lg\frac{w(S)}{w\lbrack S\rbrack}} = {{- \frac{935}{T}} + 1.375 + {\lg\mspace{11mu} f_{S}} + {\lg\mspace{11mu} C_{S}} - {\lg\mspace{11mu} a_{\lfloor O\rfloor}}}}},} & (3)\end{matrix}$ wherein L_(S)′ denotes a sulfur distribution ratiocalculated with the KTH model; T denotes the temperature, in unit of K:f_(s) denotes an activity coefficient of sulfur in the molten steel;C_(s) denotes the sulphide capacity; and a_([O]) denotes an activity ofoxygen in the molten steel; and correcting, by using the least squaremethod, the sulfur distribution ratio calculated with the KTH model toobtain an actual sulfur distribution ratio calculation formula, as shownin Formula (4):L _(S) =α+bR+cMI+dL _(S)′  (4), wherein, L_(S) denotes the sulfurdistribution ratio; R denotes a basicity of a furnace slag; MI denotes aMannesmann index of the furnace slag; a denotes a constant term; bdenotes a weight coefficient of the basicity; c denotes a weightcoefficient of the Mannesmann index; and d denotes a weight coefficientof the sulfur distribution ratio calculated by the KTH model; whereincalculating the mass of the final slag by using the LF refiningparameters and the actual sulfur distribution ratio comprises:calculating, according to a principle of sulfur mass conservation that adecreased amount of the sulfur in the molten steel equals to anincreased amount of the sulfur in the slag, the mass of the final slagin combination of a mass percent of each component in an initial moltensteel, the mass percent of each component in the target molten steel, amass percent of each component in the final slag, a mass percent and amass of each component in a casting residue, a mass percent and a massof each component in a converter tapping slag, a mass of the moltensteel and the actual sulfur distribution ratio; a final slag masscalculation model comprises:(w[S]₀ −w[S])·G_(m) =w(S)·M_(z) −w(S)_(h) ·w(S)_(c)·M_(c)  (5), wherein,w[S]₀ is a mass percent of sulfur in the initial molten steel, in unitof %; w[S] is the mass percent of sulfur in the molten steel at asmelting endpoint, in unit of % w(S) is the mass percent of sulfur inthe final slag, in unit of %; w(S)_(h) is a mass percent of sulfur inthe casting residue, in unit of %; w(S)_(c) is a mass percent of sulfurin the converter tapping slag, in unit of %; G_(m) is the mass of themolten steel, in unit of kg; M_(z) is the mass of the final slag, inunit of kg; M_(h) is a mass of the casting residue, in unit of kg; andM_(c) is a mass of the converter tapping slag, in unit of kg; andsubstituting the Formula (1) into the Formula (5) to obtain a final slagmass calculation formula, as shown in Formula (6): $\begin{matrix}{{M_{z} = \frac{{\left( {{w\lbrack S\rbrack}_{0} - {w\lbrack S\rbrack}} \right) \cdot G_{m}} + {{w(S)}_{h} \cdot M_{h}} + {{w(S)}_{c} \cdot M_{c}}}{{w\lbrack S\rbrack} \cdot L_{S}}};} & (6)\end{matrix}$ respectively obtaining, according to a principle ofmaterial conservation during the LF refining by using the LF refiningparameters and the mass of the final slag, a mass M₁ of lime required toremove the sulfur from the molten steel, a calculated mass M₂ of limerequired to adjust a basicity of refining slam and a calculated mass M₃of lime required to reach the mass of the final slag, and adding the M₁,the M₂ and the M₃, to obtain the addition amount M of the slagging limeduring the LF refining, thereby predicting the addition amount of theslagging lime; according to elemental mass conservation before and aftersulfur removal, the mass M₁ of the lime required to remove the sulfurfrom the molten steel is obtained from the following Formula (7):M₁·(% CaO)/56=G_(m)(w[S]₀ −w[S])/32  (7) according to a basic basicitycalculation formula, the calculated mass M₂ of the lime required toadjust the basicity of the refining slag is obtained from the followingFormula (8): $\begin{matrix}{{R_{1} = \frac{\begin{matrix}{{M_{c}\left( {\%\mspace{11mu}{CaO}} \right)}_{c} + {\left( {M_{1} + M_{2} + M_{y}} \right) \cdot \left( {\%\mspace{11mu}{CaO}} \right)} +} \\{{M_{l}\left( {\%\mspace{11mu}{CaO}} \right)}_{l} + {M_{h}\left( \;{\%\mspace{11mu}{CaO}} \right)}_{h}}\end{matrix}}{\begin{matrix}{{M_{c}\left( {\%\mspace{11mu}{SiO}_{2}} \right)}_{c} + {M_{l}\left( {\%\mspace{14mu}{SiO}_{2}} \right)}_{l} +} \\{{M_{h}\left( {\%\mspace{11mu}{SiO}_{2}} \right)}_{b} + M_{Si}}\end{matrix}}},} & (8)\end{matrix}$ according to the principle of material conservation, thecalculated mass M₃ of the lime required to reach the mass of the finalslag is obtained from the following Formula (9):M_(z)(% CaO)_(z)=M_(z)(% CaO)+[(M₁+M₂+M_(y))·(% CaO)]+M_(c)(%CaO)_(c)+M_(h)(% CaO)_(h)+M_(l)(% CaO)_(l)   (9); adding the M₁, the M₂and the M₃ to obtain the addition amount M of the slagging lime duringthe LF refining from the following Formula (10), thereby completingprediction:M=M₁+M₂+M₃  (10), wherein, w[S]₀ is the mass percent of sulfur in theinitial molten steel, in unit of %; w[S] is the mass percent of sulfurin the molten steel at a smelting endpoint, in unit of %; M_(z) is themass of the final slag, in unit of kg; M_(h) is the mass of the castingresidue, in unit of kg; and M_(c) is the mass of the converter tappingslag, in unit of kg; (% CaO) is a mass percent of CaO in the lime, inunit of %; M₁ is the mass of the lime required to remove the sulfur fromthe molten steel, in unit of kg; G_(m) is the mass of the molten steel,in unit of kg; M₂ is the calculated mass of the lime required to adjustthe basicity of the refining slag, in unit of kg; M_(l) is a mass ofpre-melting refining slag added during tapping, in unit of kg; M_(y) isa mass of lime added during; the tapping, in unit of kg; M₃ is thecalculated mass of the lime required to reach the mass of the finalslag, in unit of kg; M_(Si) is a mass of silicon dioxide generatedduring ferrosilicon deoxidation, in unit of kg; (% CaO)_(c) is a masspercent of CaO in the converter tapping slag, in unit of %; (% CaO)_(l)is a mass percent of CaO in the pre-melting refining slag added duringthe tapping, in unit of %; (% CaO)_(h) is a mass percent of CaO in thecasting residue, in unit of %; (% CaO)_(z) is a mass percent of CaO inthe final slag, in unit of %; (% SiO₂)_(c) is a mass percent of SiO₂ inthe converter tapping slag, in unit of %; (% SiO₂)_(l) is a mass percentof SiO₂ in the pre-melting refining slag added during the tapping, inunit of %; (% SiO₂)_(h) is a mass percent of SiO₂ in the castingresidue, in unit of %; and R₁ is a basicity of a target refining slagand is calculated by a thermodynamic simulation.
 4. The LF refiningmethod according to claim 3, wherein the parameters comprise: inboundparameters, outbound parameters and production parameters; the inboundparameters comprise a mass percent of each component in an inboundmolten steel, the mass of the molten steel, the mass percent of eachcomponent in the converter tapping slag, the mass of the convertertapping slag, the mass percent of each component in the casting residue,and the mass of the casting residue; the outbound parameters comprisethe mass percent of each component in the target molten steel, and themass percent of each component in the target slag; and the productionparameters comprise a mass percent of each component in the lime, and amass of the lime.